Quantitative micellar chromatographic analysis of interaction between peptides and sodium dodecyl sulfate micelles

Abstract

Interaction between short, water-soluble peptides and sodium dodecyl sulfate (SDS) micelles was analyzed by chromatography of the peptides on a Sephadex G-50 M el bed in an eluent containing the micelles. Peptides that interacted with the micelles showed intermediate elution volumes. In the absence of micelles in the eluent, the peptides (7–16 amino acid residues) were eluted near the total volume, whereas micelles applied as a sample appeared at the void volume. The association constants, K A, were calculated from the capacity factors k′ obtained at different SDS micelle concentrations. The range of the K Avalues was (0.5–11) × 10 4 M −1. As a rule, the longest peptides and the positively charged ones interacted most strongly with the micelles, but the amino acid sequences also affected the interaction. Partially hydrophobic peptides that may correspond to interfacial segments of a transmembrane protein, the glucose transporter Glut1, showed relatively weak interactions with SDS micelles. The peptide interaction with sodium 1-decane sulfonate micelles supplemented with SDS was similar to that with SDS micelles, whereas none of several peptides tested interacted significantly with micelles of the non-ionic detergent n-dodecyl octaoxyethylene. The peptide-micelle interaction was proposed to occur mostly at the micelle surface as in the protein-decorated micelle structure for SDS-protein complexes.